SD Card / Android Dart not syncing newly added files/music

Greetings all. Sorry if this is posted in the wrong place, new person here.

I have a Samsung Dart Phone and SD Card which I now use just for music (it's probably 5-6 years old now and sometimes I really want to switch my SIM card back to it, it was fantastic and small/compact, but I digress).

It appears that the SD card on it is not syncing up new music/files that I am adding when connected via USB cord. It acts like it reverts or updates to a previous date. This started happening I'd say about 1 1/2 months ago. Has plenty of music on it already, but again nothing new I add to it will sync.

I validated this even further by buying two new songs online and downloading to my computer and trying to copy them over to the phone this evening, and the same results (or lack thereof).

I tried doing a few things - copying/backing up my music then doing a factory restore of the device, clearing the cache on the Music app on the device did no good, then experimenting this evening I performed a Factory Restore.

This seems to do the job, it takes some time but once the phone gets going again, I can plug it into my computer via USB, and then all my music I have on the SD card - old and new, gets recognized.

However, this is just a band-aid solution.

If I turn the device off then back on, the SD card goes back to its previous behavior, and won't sync anything new again. Basically I'd have to keep restoring factory default settings.

I certainly don't mind doing this for the time being as again I just use the device for music, but there has to be some better alternatives. Is my SD card just simply old/corrupt?

I got this resolved, not in the most ideal way but to where I am whole again for the most part.

Sunday morning after going the factory restore way once more, I could not get my phone to read the SD card at all, no music, nothing (and before a very long run outdoors, I NEEDED my music, ack! Oh well.).

I decided to try to format the SD Card from scratch - I was aware that everything was going to be wiped out. I didn't back up my files/music on my card per se but took note of them through screen captures and such.

It was tedious and took some time yesterday but I was able to get most of my music files back on the SC card through USB through the traditional copy/paste.

I don't have to do factory restores anymore, the SC card at least for now is fresh and new and hopefully stays that way. Restarting the device, all the music was still there and I was able to bike/workout more happily this early morning.

If I decided to buy a new SD card, I was going to have to go through this process anyways, so might as well have tried it with the SD card I had, and thankfully it worked out.